PDA

View Full Version : MiLBOT 1st cnc machine



muzzammil1444
11-26-2005, 04:45 AM
Hi, I'm newbie here.. :D

I'd start a few month ago trying to built a small cnc machine for foam-cutting purpose, and marker-plotting..

Here about a few pictures about the model I'd build..
For x-axes i used an old printer Canon 100sp (2 units), and y-axes I used old printer Lexmark Z23 (1unit).. I'd modified a part of Lexmark printer for Z-axes..
But the z-axes couldn't move in a straight line..
But in a few of rotational movement..
Hmm, abnormal movement..? (chair)

Hmm, I'd build a hardware too, but maybe I'll test the circuit this week..

I really appreciate any suggestion and advice.. :D

muzzammil1444
11-27-2005, 02:41 AM
Hello :D

I've trying to run the hardware but the motor is getting hot and rigid. And it won't move.

I used Kcam4 software to interface with the hardware..
I have read a data sheet of L297 ic (STMicroelectronics) and it state that this ic can used for bipolar motor and unipolar motor (4 phase permanent magnet motor). But I'm not sure if the stepper motor I used is a type of unipolar (4 phase permanent magnet) or not..

I have a question about a holding torque, pull out torque and pull-in torque.. (kindly please refer the datasheet :P) Could anyone explain about it?
And how about to convert the unit pps to rpm? Is it pps means pulse per second?

Thanks a lot..

abasir
11-27-2005, 07:44 PM
pps:Pulse per second
RPM:Revolution per minute
SPR:Steps per revolution (typical stepper is 200)
RPM=pps/SPR

Based on datasheet, the stepper is 48spr (360 deg/7.5deg) and unipolar (5 wires). Cannot be bipolar driven because the coil shares the common wire. See http://www.cnczone.com/forums/showthread.php?t=15097

pminmo
11-27-2005, 11:12 PM
Hello :D

I've trying to run the hardware but the motor is getting hot and rigid. And it won't move.

I used Kcam4 software to interface with the hardware..
I have read a data sheet of L297 ic (STMicroelectronics) and it state that this ic can used for bipolar motor and unipolar motor (4 phase permanent magnet motor). But I'm not sure if the stepper motor I used is a type of unipolar (4 phase permanent magnet) or not..

Thanks a lot..

The L297 by itself is not mean to directly drive a stepper. It needs to be follwed a driver like a L298 for bipolar. To get an L297 to work with unipolar motors, you need some external "and" logic and drivers such as fets or transistors. 4 wire motor is bipolar only, 5 wire motor is unipolar only, 6 and 8 wire motors can be wired for either a unipolar or bipolar motor. If your motor is getting hot quickly with no movement, you have a problem. It needs to be figured out without a motor attached. Looking at your pictures, it looks lik you may also have an L298 driver? If so it will run the motor wired as bipolar. You also need to set the vref for a maximim current appropriate for the motor.

muzzammil1444
11-30-2005, 09:55 AM
pps:Pulse per second
RPM:Revolution per minute
SPR:Steps per revolution (typical stepper is 200)
RPM=pps/SPR

Based on datasheet, the stepper is 48spr (360 deg/7.5deg) and unipolar (5 wires). Cannot be bipolar driven because the coil shares the common wire. See http://www.cnczone.com/forums/showthread.php?t=15097

Thanks a lot for the information..

So I guess that the motor i used are bipolar (4 wires)?
Actually for the Canon printer i've opened out, it used 2 type of motor which are 5-wires of step-motor.. and the other are 4-wires..

Lexmark printer used 2 type of motor which are dc motor, and 4-wires of step motor..

i didn't have the picture yet, but maybe I'll upload it later.. :p

muzzammil1444
11-30-2005, 10:07 AM
The L297 by itself is not mean to directly drive a stepper. It needs to be follwed a driver like a L298 for bipolar. To get an L297 to work with unipolar motors, you need some external "and" logic and drivers such as fets or transistors. 4 wire motor is bipolar only, 5 wire motor is unipolar only, 6 and 8 wire motors can be wired for either a unipolar or bipolar motor. If your motor is getting hot quickly with no movement, you have a problem. It needs to be figured out without a motor attached. Looking at your pictures, it looks like you may also have an L298 driver? If so it will run the motor wired as bipolar. You also need to set the vref for a maximum current appropriate for the motor.

Thanks pminmo..
Sure I used both L298 and L297 ics.
And the step-motor are 4-wires..



You also need to set the vref for a maximim current appropriate for the motor
Actually, I used 1 unit of power supply. Is it ok if I use 2 unit to increase the vref for a maximum current..?

venomx999
12-03-2005, 12:12 PM
Hey, I come to find out that our motors the M42Sp-series are bipolar wired.

I am thinking of open it up and find the other wires to convert it back to unipolar.

By the way, your control boards look good but not functioning correctly with the motors ?
I have the same problem.

pminmo
12-03-2005, 01:29 PM
Thanks pminmo..
Sure I used both L298 and L297 ics.
And the step-motor are 4-wires..

Actually, I used 1 unit of power supply. Is it ok if I use 2 unit to increase the vref for a maximum current..?

Looking at your picture, I don't see a resistor that I would consider appropriate for the current sense resistor unless you have a really low current motor? If so what is the value and wattage of the resistor, and what is the current rating of your motor?

venomx999
12-03-2005, 06:24 PM
muzzammil1444,

I got to give you some appraisals... you are one innovative thinker.

The gantry you are building is unique and never been done before. Let me know how it turns out :)

As for my mill, im determine to cast alluminum parts for it. The wooden one is a model, then follow by cast-alluminum parts to replace.

This process will take me months :(